With the popularity of the Internet, people begin to establish and develop interpersonal relationship with others online. According to the newest report from China Internet Network Information Center, 95.6% Internet users accesses to social networking software, and adolescents aged 10-19 years old account for 17.5%. However, excessive reliance on online social networking may have serious negative effects on one’s physical and mental health. Therefore, exploring the factors and mechanisms of cyber-relationship addiction can be helpful for further prevention and intervention. Parent-child technology interference may be a crucial family factor in causing adolescent cyber-relationship addiction. Moreover, previous studies also indicated that relative deprivation was a potential mediator in the relationship between parent-child technology interference and cyber-relationship addiction. Meanwhile, internal-state-awareness can be the protecting factor for relative deprivation. According to the “attenuation” model, internal-state-awareness may interact with parent-child technology interference. In sum, this study constructed a moderated mediation model to reveal the relation between parent-child technology interference and cyber-relationship addiction. Specifically, we tested the relationship between parent-child technology interference and cyber-relationship addiction of adolescents, the mediating effect of relative deprivation, and the moderating effect of internal-state-awareness. A total of 1637 senior high school students (mean age = 16.19 years, SD = 3.82 year; 648 boys and 705 girls) were recruited to participate in this investigation. After given informed consents, they completed Parent-Child Technology Interference Scale, Cyber-relationship Addiction Questionnaire, Relative Deprivation Questionnaire and Internal-State-Awareness Scale. First, common method biases were examined. Then the overall relationships between the variables in the hypothesized model was obtained by correlation analysis. Finally, the proposed moderated mediation model was tested by AMOS. The correlation analysis showed that: parent-child technology interference was positively correlated with cyber-relationship addiction, and relative deprivation was positively correlated with parent-child technology interference and cyber-relationship addiction. After controlling for gender, the testing for moderated mediation model indicated that: (1) Parent-child technology interference significantly contributed to cyber-relationship addiction in senior high students; (2) Relative deprivation played a mediating role in the relationship between parent-child technology interference and cyber-relationship addiction; (3) Internal-state-awareness moderated the mediated path through relative deprivation, with the effect being stronger for adolescents with higher internal-state-awareness. Therefore, both mediating and moderating effects existed in the association between parent-child technology interference and cyber-relationship addiction. The present study revealed how and when parent-child technology interference affected cyber-relationship addiction of adolescents. These findings may contribute to the precaution and prevention of cyber-relationship addiction of adolescents. First, parents should reduce the frequency of using electronic devices during the interaction with their children. Meanwhile, parents should give appropriate response to their children. Second, parent-child technology interference can affect cyber-relationship addiction of adolescents through relative deprivation. The subjective experience of relative deprivation can be diminished through cognitive training. Thus, it is helpful to reduce the risk of adolescent cyber-relationship addiction by learning appropriate cognitive strategies.